Paper feeder and printer

ABSTRACT

A paper feeding apparatus of this invention comprises a feed roller and a paper holding member for nipping and feeding roll paper; and a first paper guide that has a first guide surface against which the roll paper outputted from the feed roller is pushed. The first guide surface is tilted so as to guide the roll paper in a direction opposite to a curving direction of the roll paper. In this paper feeding apparatus, the roll paper is pushed against the guide surface for removing the curl. Therefore, the curl is removed efficiently. The mechanism for removing the curl becomes simple and load of motor is reduced. The paper feeding apparatus can be applied to a compact printer that is carried with a mobile phone.

TECHNICAL FIELD

The present invention relates to a printing apparatus and a paperfeeding apparatus that can correct the curl of roll paper.

BACKGROUND ART

Printing apparatuses, such as printers and fax machines that print ontoroll paper are conventionally known. Compared to apparatuses that printonto cut sheets, such printing apparatuses require less space forstoring printing paper and so can be produced in more compact overallsizes. However, the curling tendency of roll paper causes problems whenprinting on roll paper. The curling tendency remains for roll paper thathas been printed upon and outputted from a printing apparatus, so thatsuch paper curls after output. This means that even if the printed paperis cut into a predetermined size, such as Japanese A4 size, when it isoutputted from a printer, it is not possible to store the printed paperin a stack in a paper stocker or the like. Since the outputted papersheets are curled, it is more difficult to gather a plurality of sheetstogether in a bundle and file the sheets. Accordingly, printing paper inthe form of sheets or pre-cut sheets are preferred at present forprinting, and printers and fax machines are made large in order to storeprinting paper in the form of sheets.

The increasingly widespread use of mobile terminals such as PDAs andmobile telephones has been accompanied with strong demands for compactprinters that can be used together with such devices even if the user isout of office. While printers that use roll paper as the printing paperare suited to being made compact, for such printers to be easy to use,it is important to correct, remove or straighten the curling tendency(the curl) of the roll paper using a compact mechanism. In particular,since a compact printing apparatus for a mobile terminal such as a PDAwill need to use roll paper with a diameter of around 10 mm or less, theprinted paper (“print out”) outputted will be sure to curl and ends upcurling up with a diameter of 10 mm or less. Compared to print outs thathave curled up with a large diameter, print outs that have curled upwith a small diameter are much more difficult to handle, so that itbecomes very important to correct the curling tendency.

A mechanism in which roll paper is pressed by a paper guide with asharp-angled tip using a spring or other force can conceivably be usedas a mechanism for removing the curl of roll paper. However, sincesetting the paper guide with the sharp-angled tip on the paper passmakes the paper route being changed, and a space for the spring forpressing the paper guide onto the paper is necessary, a large space isoccupied by the mechanism for correcting the curl. Accordingly, it isnot possible to realize a compact printer. Also, the curl-correctingperformance is not especially high, so that there is the fundamentalproblem that the method of the above is essentially not effective forroll paper with a small diameter.

Also, since the roll paper is additionally held by the paper guide andthe spring on the paper pass, there is increased resistance for paperfeeding, which makes it necessary to use a motor with an output that canhandle this load. Accordingly, the size of the motor increases and powerconsumption also increases, which makes this technology even less suitedto the realization of a compact printer.

In addition, since the roll paper is held by the paper guide with thesharp-angled tip and the spring on the paper pass, when the printer is astandby mode, the roll paper is continuously held by the sharp-angledtip, so the held part becomes curled in the opposite direction.Accordingly, print-outs become a paper curled as a whole in the samedirection as the roll paper but have tips that curl in the oppositedirection, such print-outs are extremely difficult to handle and alsohave a poor appearance. It is possible to prevent curling in theopposite direction through methods such as moving the spring away whenthe printer is in standby mode, though enclosing a mechanism for doingso further increases the size of a printer and also increases the cost.

For this reason, it is an object of the present invention to provide apaper feeding apparatus that is compact and is capable of correcting thecurling tendency of roll paper and also a printing apparatus equippedwith such paper feeding apparatus. It is a further object to provide apaper feeding apparatus that can suppress increases in the load of amotor and does not impart a tendency in. the opposite direction, andalso a printing apparatus equipped with such paper feeding apparatus. Itis yet another object to provide a printing apparatus that uses rollpaper as the printing paper, is easy to use, and is extremely compact soas to be well suited to being carried together with a mobile terminalsuch as a mobile phone.

DISCLOSURE OF THE INVENTION

For the above reason, the present invention includes a surface which istilted in an opposite direction to the direction in which the roll paperis bent or curled and against which outputted roll paper is pushed by acoordinated operation by a paper holding plate, such as a sub roller orplaten, and a feed roller, with this tilted surface being struck by theroll paper and the paper feeding force and the rigidity or resistance tobeing folded over of the roll paper itself (folding resistivity of thepaper) being used to remove the curling tendency. The paper feedingapparatus of the present invention comprises: a feed roller and a paperholding member for nipping (holding) and feeding roll paper; and a firstpaper guide that has a first guide surface against which the roll paperoutputted from the feed roller is pushed and the first guide surface istilted so as to guide the roll paper in an opposite direction to acurving direction.

With this paper feeding apparatus, there is no holding and stretching ofthe roll paper on the paper route or pulling and stretching of the paperin the opposite direction to the paper feeding direction, so that thereis almost no increase in the load when feeding the paper. The roll paperstrikes the first guide surface at an exit of the feed roller, so thatsomewhat of a load is generated, but since the paper is fed in a largelyfree state along the first guide surface without the paper being held,pulled or stretched, compared to methods that remove curl by holding thepaper, the increase in the load of the motor that is required to removethe curl can be halved or reduced even more.

Experiments by the inventors have confirmed that the paper feedingapparatus of the present invention is capable of removing the curlingtendency of roll paper with extremely high efficiency. In the paperfeeding apparatus of the present invention, roll paper with a curlingtendency strikes the first guide surface at the exit of the feed rollerand the roll paper is fed so as to bend in the opposite direction to thecurl or curving direction. By disposing the first guide surface near thefeed roller and/or providing a paper guide that guides both surfaces ofthe roll paper between the feed roller and the first surface and guidesthe roll paper to the first guide surface without sagging significantly,the rigidity or strength of the roll paper itself can be used to pushthe roll paper against the first guide surface with a strong force.Accordingly, the roll paper that is fed by the feed roller bends sharplyin the opposite direction to the curling tendency at the point thatstrikes the first guide surface. Also, the roll paper itself hasrigidity (resistance to being folded over), so that a sufficient forcefor pressing the roll paper against the first guide surface and sharplybending the roll paper is transmitted from the feed roller via the rollpaper itself to the part of the roll paper that strikes the first guidesurface. As a result, it is thought that, at the first guide surface,the part of roll paper bends in the opposite direction to the curlingtendency with extending or stretching the part, thereby removing thecurl with high efficiency.

In this paper feeding apparatus, when the printer is in a standby state,the roll paper is not being fed by the feed roller; therefore, the rollpaper is not strongly pressed against the first guide surface. Thismeans that curling of the roll paper in the opposite direction isavoided.

The paper feeding apparatus of the present invention has merits thatload on the motor for feeding paper is little, the curling tendency isefficiently removed and the imparting of curve in the opposite directionis avoided. In addition, the paper feeding apparatus has an extremelysimple construction of a first paper guide with a first guide surface, afeed roller, and a paper holding member, so that a compact paper feedingapparatus that can efficiently remove the curling roll paper isprovided. By installing the paper feeding apparatus of the presentinvention in a printing apparatus, it is possible to provide a compactprinting apparatus that uses roll paper. The printer of this inventionis easy to use since it outputs roll paper with the curling tendencyremoved, and is compact and so suited to being carried with a mobileterminal, such as a mobile phone.

In the paper feeding apparatus of the present invention, it ispreferable for the first paper guide to be disposed in the vicinity ofthe feed roller and in particular for the distance between the feedroller and the first guide surface to be 10 mm or below. When the firstpaper guide is disposed in the vicinity of the feed roller, the rollpaper can be prevented from sagging between the first guide surface andthe feed roller, and the rigidity (strength, stiffness) of the rollpaper is used so that the roll paper can be reliably pushed against thefirst guide surface. Accordingly, it is possible to reliably remove thecurl. In addition, since the feed roller is near the first paper guidein this layout, the paper feeding apparatus becomes compact.

By tilting the first guide surface by 45 degrees or above with respectto the direction in which the roll paper strikes the first guidesurface, almost sufficient slant for removing the curl can be produced.However, the strength of the curling tendency of the roll paper isinfluenced by the diameter of the roll paper and the quality of thepaper rolled. The strength of the curling tendency differs between thefirst part of the roll paper and the end part of the roll paper, anddiffers according to the diameter of the roll paper. Accordingly, it ispreferable to provide a means that can adjust or change the angle (orslant) of the first guide surface and/or the distance (or gap) betweenthe first guide surface and the feed roller, so that curling tendenciesof different strengths can be flexibly corrected by changing the angleby which the roll paper is forced to bend.

It is effective to provide a second paper guide that has a second guidesurface for guiding or leading the roll paper outputted from the feedroller to the vicinity of the first paper guide. Using the second guidesurface, the position and angle at which the roll paper outputted fromthe feed roller strikes the first guide surface becomes easilyadjustable according to the construction of the printer and the strengthof the curling tendency. It is also possible, by the second guidesurface, to maintain the conditions and/or the positional relationshipbetween the roll paper and the first guide surface for efficientlyremoving the curling tendency. For example, the second guide surface canprevent moving the point where the roll paper strikes the first guidesurface on that surface as the paper is fed. The moving of the pointwhere the roll paper is bent reduces the angle by which the roll paperis forced to bend in the opposite direction and becomes the ability toremove the curling tendency unstable.

It should preferably be possible to adjust the angle of the first guidesurface according to the strength of the curl of the roll paper. Whenthe first paper guide is close to the contact point between the feedroller and the roll paper, when the first paper guide is rotated inorder to adjust the angle of the first guide surface, it is easy for thefirst paper guide and feed roller to interfere with one another.Accordingly, the range of angle of the first guide surface would belimited and it may sometime cause difficult to efficiently remove thecurling tendency. On the other hand, when the first paper guide and feedroller are placed apart, the roll paper sags between them and it maycause no longer possible to make use of the rigidity (resistance tobeing folded over) of paper itself. When a second paper guide isprovided, it is possible to guide the roll paper in a straight line withrespect to the first guide surface that is disposed at a positionsomewhat distant from the feed roller, so that the rigidity of paperitself can be used and the roll paper can be pushed onto the first guidesurface. At the same time, the distance or gap from the feed roller tothe first guide surface can be secured, so that the angle of the firstguide surface can be set at the most suitable angle for removing thecurl.

It is possible to integrate the paper holding member and the secondpaper guide. As one example, the paper holding member may be a paperguide with a part that presses the roll paper onto the feed roller fornipping and a flat guide surface that guides the roll paper as far as avicinity of the first guide surface. When the first paper guide iscomparatively far from the feed roller, it is preferable to provide afourth paper guide that has opposing guide surfaces so that the rollpaper is guided from the output side of the feed roller to the firstguide surface. A part of the fourth paper guide on the output sidefunctions as the second paper guide.

It is important for the distance or gap between the second guide surfaceand the first guide surface to be short enough for the foldingresistivity of the paper to be used for pressing or pushing. As oneexample, it is preferable for the distance between the output end of thesecond guide surface and the first guide surface to be 5 mm or less. Bymaking the corner of the output end of the second paper guide at a rightangle or an acute angle, it is possible to stably push the roll paperonto the first guide surface at an angle at which the curl can beremoved.

In order to adjust the ability to remove the curl of the roll paper, itshould preferably be made possible to adjust the gap (or distance)between the second guide surface and the first guide surface and/or theangle between (or slope of) the first guide surface and the second guidesurface. The strength of the curling tendency is influenced by thediameter of the roll paper and the strength of the curling tendency isdifferent at the start and at the end of the roll paper, with suchdifferences tending especially large for roll paper with a smalldiameter. For this reason, it is preferable to provide means forindicating, in relation to a remaining diameter of the roll paper, anadjustment amount for a means for adjusting so as to make it possiblefor the user to easily control the distance and/or angle. The means foradjusting the distance and/or angle may make adjustments automaticallyin coordination with the remaining diameter.

When the paper feeding apparatus of the present invention is used in aprinting apparatus, the printing mechanism such as the print head may beprovided separately. Also, a line thermal head can be made to functionas both the print head and the paper holding member. A platen roller isset as the feed roller, and the roll paper is nipped and fed by theplaten roller and the line thermal head. In this printing apparatus, thepaper feeding apparatus for removing the curl of roll paper and theprinting mechanism is integrated. Accordingly, it is possible to providea compact, low-cost printing apparatus that can efficiently de-curl witha small number of components. A line thermal printing apparatus does notneed consumables such as ink, and so is even more suited to a compactprinting apparatus.

In a printing apparatus where the first paper guide is a flat platen anda print head prints onto roll paper that is supported on the first guidesurface, the printing mechanism and the paper feeding apparatus can beintegrated or can use common parts, so that a compact, low-cost printingapparatus can be provided. The print head can be a line-type head or aserial printer, the serial printer head moving along the first guidesurface. One example of a serial-type print head is an ink jet type.

When printing onto roll paper, it is customary to print on the outersurface of the roll paper. However, if the roll paper, the feed roller,and the print head are arranged in a line in that order to makemaintenance and the setting of the roll paper easy, the printed surfacefaces downwards. An arrangement where a printing apparatus is attachedto the top of a mobile terminal is preferable. In such cases, from theprinter integrated with the mobile terminal, the printed roll paper isdischarged towards the terminal and the paper will hide the screen ofthe mobile terminal.

Another problem is that, in order to correct a strong curling tendency,it is necessary to increase the slope or angle of the first guidesurface. When the roll paper has a small diameter, it is necessary touse an angle of close to 90 degrees or above. To place the first paperguide upright and discharge the roll paper in a state where the printedsurface appears as the surface and the paper does not cover the surfaceof a mobile terminal, the print head has to be arranged horizontallyabove the feed roller. This arrangement is not preferable since theprint head has to be removed when setting the roll paper and when thereis a paper jam.

These problems are solved by guiding the inner surface of the rollpaper, which is fed by the feed roller, by the first guide surface sothat the discharge direction of the roll paper is changed to the outersurface. Since the roll paper is bent in the opposite direction to thedirection of curving due to the curling tendency, the curl becomes easyto remove. Also, since the roll paper discharged to the supply directionof the roll paper, the roll paper is outputted without covering thescreen of the mobile terminal. In addition, the inner surface appears asthe surface of the discharged roll paper, so that by printing on theinner surface, it is possible to output the paper with the printedsurface on the front. In this printing apparatus, since the roll paperis discharged to the direction in which the roll paper is supplied, thefeed roller can be disposed on the roll paper side with respect to theprint head, so that the feed roller (for example, the platen roller) canbe arranged removable, not the print head, for changing the roll paper.

Accordingly, in a printing apparatus equipped with the paper feedingapparatus of the present invention, it is preferable for a paper pass orroute that leads the inner surface of the roll paper to the print headto be provided. The inner surface of the roll paper is guided by thefirst guide surface to discharge the roll paper towards the outersurface. The feed roller is arranged so as to contact the outer surfaceof the roll paper and feed the roll paper towards the first guidesurface. Accordingly, when a thermal head is used as the print head,roll paper with a thermosensitive surface on the inner surface is used.

By providing a cutter for cutting the roll paper into a desired size, itis possible to obtain print outs that have no curling tendency, thathave been cut into the desired size, and that can be handled in the sameway as pre-cut sheets. If a movable blade is disposed between the firstpaper guide and the feed roller, the paper feeding amount for cuttingthe roll paper is reduced. By cutting the roll paper upstream on thefirst guide surface, counter curling tendency at the first guide surfaceis more reliably prevented. The second guide surface can be used tocontrol the distance between the print head and the cutter, so that itis easy to provide enough space for arranging the cutter.

When the roll paper is cut by a movable blade and a fixed blade, it ispreferable for the movable blade to be disposed on the outer side to theroll paper, that is, above the feed roller and/or on the discharge sideso as to make the movable blade easy to remove. On the other hand, it ispreferable for the fixed blade to be disposed on the print head side andon an opposite side of the first paper guide to the movable blade, thatis, below and/or on the paper feeding side. Even when the printingapparatus stops due to a paper jam or the like with the movable bladehaving moved and being positioned above the fixed blade, the fixed bladedoes not obstruct the removal of the movable blade.

As mentioned, in a printing apparatus that prints on the inner surface,it is easy to arrange the first paper guide, the movable blade and thefeed roller removable from the main body of the printing apparatus. Whenthe first paper guide, the movable blade, and the feed roller areremovable from the main body, the entire paper route appears, so that itis extremely easy to set the roll paper, and it is also simple to removepaper jams. The first paper guide, the movable blade, and the feedroller become removable with a roll paper cover that opens and closeswith respect to the main body when the roll paper is attached. Simplyopening the roll paper cover exposes the entire paper route, setting theroll paper and dealing with paper jams become much easy. If the firstpaper guide has the roll paper discharged in the direction of the rollpaper cover, the surface of the roll paper cover can be used as astocker.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing the overall construction of aprinter according to the present invention.

FIG. 2 shows an enlargement of a part that composes the paper feedingapparatus of the printer shown in FIG. 1.

FIG. 3 shows an example of a printer with a separate second paper guidebetween the feed roller and the first paper guide.

FIG. 4 shows an example modification of the printer shown in FIG. 3.

FIG. 5 shows another example of a printer of the present invention.

FIG. 6 shows yet another example of a printer of the present invention.

FIG. 7 shows a printer according to the present invention that prints onan inner surface of roll paper and has been installed in a mobileterminal.

FIG. 8 is a cross-sectional view showing the overall construction of theprinter shown in FIG. 7.

FIG. 9 shows the printer shown in FIG. 7 in a state where the roll papercover has been opened.

FIG. 10 shows the printer shown in FIG. 7 in a state where the rollpaper cover has been closed after the roll paper has been set.

FIG. 11 shows how printing is performed on roll paper with a largediameter.

FIG. 12 shows how printing is performed on roll paper with a smalldiameter.

BEST MODE FOR CARRYING OUT THE INVENTION

The following describes the present invention in more detail withreference to the attached drawings. FIG. 1 is a cross-sectional viewshowing a printer (printing apparatus) according to the presentinvention in outline, in a state where a housing 2 has been cut on aside surface thereof. This printer 1 is a thermal printer. The printer 1has a line thermal head 15 and a platen roller 16 for nipping andfeeding and prints onto thermosensitive roll paper 3. This printer 1 isarranged in a box-shaped housing 2 and a total thickness is almost 15mm. The housing 2 includes a paper storage unit 11 for the roll paper 3at one side (the front) F. The housing 2 is divided into a roll papercover 27 that covers the upper part of the paper storage unit 11 and apart that forms a main body 28 of the printer 1. The cover 27 isattached to the main body 28 via a hinge 13 so that the cover can beopened and closed. When the cover 27 is opened to the front, roll paper(a roll paper unit) 3 r that has a width of around 105 mm and a diameterof around 12 mm can be set.

The back side B of the housing 2 is a part 12 where printing isperformed on the roll paper 3 and encloses a printing mechanism 10 thatcomprises the line thermal head 15 and the platen roller 16 and otherprinting-related mechanisms, such as a motor 18 for driving the platenroller 16 and a control panel 23. After the roll paper 3 supplied fromthe paper storage unit 11 has been printed upon by the printingmechanism 10, the roll paper 3 is outputted to the outside from adischarge opening 4 provided in the upper part or an upper wall 2 a ofthe housing 2. A manual cutter 5 is provided at the discharge opening 4.By manually cutting the outputted roll paper 3, print outs in the formof cut sheets of A6 size (105 mm by 148 mm) are obtained. Although notillustrated, the printer 1 has a suitable interface, such as a USBinterface or an infra red interface, for receiving printing data andcontrol data from a host, which can be a mobile phone or mobilecomputer, such as a PDA, or a desktop personal computer.

When the printer 1 is set so as to the discharge opening 4 being locatedat the top, the line thermal head 15 and the platen roller 16 arearranged up and down. The platen roller 16 has a highly frictional outercircumferential surface that is made of rubber or the like, and reliablyfeeds the roll paper 3 with the roll paper 3 being held or nippedbetween the line thermal head 15 and the platen roller 16. A feed guide17 is provided below and behind the platen roller 16 and leads the rollpaper 3, which has been supplied from the paper storage unit 11 at thefront F, below the platen roller 16. The roll paper 3 moves by around180 degrees around the platen roller 16, changes the direction and leadsto the line thermal head 15. An outlet guide 25, which has a guidesurface (first guide surface) 30 that extends diagonally upwards fromthe periphery of an output side of the platen roller 16, is disposed atthe discharge opening 4. The line thermal head 15 is equipped with ahead part 22 that has a printing surface 15 a for performing printing byheating the roll paper 3, and is disposed at a position contacting theplaten roller 16. Also, a plate part 21 extends towards the dischargeopening 4 from the head part 22, with a tip or end part 21 a of theplate part 21 reaching a vicinity of or a point close to the guidesurface 30.

FIG. 2 shows an enlargement of the relationship between the line thermalhead 15, the platen roller 16 and the outlet guide 25. The line thermalhead 15 and the platen roller 16 feed the roll paper 3 along a downwardsurface (second guide surface) 19 of the plate part 21 of the linethermal head 15 in the front direction F (a first direction (φ1). Theroll paper 3 strikes the guide surface 30 of the outlet guide 25 and isbent upwards along the slant of the guide surface 30, and then the paper3 is outputted from the exit opening 4. The slant S (an angle θ in theclockwise direction with respect to the first direction φ1) of the guidesurface 30 is tilted so as to bend the roll paper 3 in an oppositedirection to the direction of curl. In the present embodiment, the slantS is tilted by around 50 degrees in the clockwise direction with respectto the first direction φ1 in which the roll paper 3 is conveyed.Accordingly, a point or part 3P of the roll paper 3 that strikes theguide surface 30 is bent in the opposite direction to the direction inwhich the roll paper 3 is curled and an inside of the curled part isstretched or extended. Accordingly, the curve due to the curlingtendency is removed and the roll paper 3 is outputted from the exitopening 4 as flat continuous paper. Therefore, by cutting the roll paper3 into a predetermined size such as A6 using the cutter 5, it ispossible to obtain the same print outs as pre-cut sheets of the desiredsize using roll paper 3.

In the printer 1, a paper feeding apparatus 40 of the present inventionis arranged by the platen roller 16, the thermal head 15, and the outletguide 25 and by those parts the printing mechanism 10 is also arranged.That is, the platen roller 16 corresponds to a feed roller, the thermalhead 15 corresponds to a paper holding member, and the outlet (dischargeor output) guide 25 corresponds to a first paper guide that has a firstguide surface. Also, in the thermal head 15, the tip part 21 a of theplate part 21 that extends towards the guide surface 30 on the outputside of the thermal head 15 corresponds to a second paper guide. Thismeans that the line thermal head 15 also functions as a third paperguide in which the paper holding member and second paper guide areintegrated.

The guide surface 30 having the slant S tilted so that the roll paper 3is bent in the opposite direction of the bent of the roll paper 3 isenough for de-curling the roll paper 3. However, according toexperiments by the inventors of the present application, if the slant Sof the guide surface 30 is tilted by 45 degrees or above with respect tothe first direction φ1 in which the roll paper 3 strikes the first guidesurface 30, the curl of the roll paper 3 becomes reliably removed, andprint outs becomes in an approximately flat state. Accordingly, in orderto obtain print outs that can be handled in the same way as regular cutsheets, the angle θ of the slant S of the first guide surface 30 shouldpreferably be 45 degrees or above with respect to the first directionφ1.

When there is no special paper guide to guide the roll paper 3 to theguide surface 30, it is important for the first guide surface 30 to bedisposed close to the platen roller 16 that functions as the feedroller, and the arrangement that the distance R between the platenroller 16 and the first guide surface 30 is 10 mm or below ispreferable. As described below, this distance can be extended bydisposing a suitable paper guide. In the paper feeding apparatus 40 ofthe present invention type, even if the roll paper 3 may be bentsomewhat due to its own curling tendency, the roll paper 3 is led in anapproximately linear manner to the first guide surface 30 using therigidity of the roll paper itself. At the point (3P in the drawing), thepaper 3 strikes the first guide surface 30 and the paper 3 is bent withstretching and/or extending sharply in the opposite direction to thecurling tendency, so that the curl is removed. The inner surface 3 a ofthe curled roll paper 3 is pressed or pushed onto the guide surface 30and is forcibly bent in the opposite direction to the curl, so that theinner surface 3 a extends or being stretched and the outer surface 3 bcontracts or shrinks, so that it is believed that the imbalance in theinner stress of the roll paper 3 that causes the curling tendency isremoved and the curl is removed extremely efficiently.

In order to suddenly change the angle of the roll paper 3 at the part 3Pthat strikes or contacts the first guide surface 30, the roll paper 3should preferably be pushed against the guide surface 30 with sufficientforce. To do so, it is important for the power of the platen roller 16to be transmitted to the point 3P using the rigidity of paper itself(resistance to folding of the roll paper itself), so that it isimportant for the roll paper 3 to not bend or sag between the platenroller 16 and the guide surface 30. Accordingly, in the printer 1 of thepresent embodiment, it is preferable for the guide surface 30 to bedisposed as close as possible to the platen roller 16 within a rangethat is tolerated due to layout and assembly considerations.

Since the roll paper 3 curls downwards, a force that pushes the rollpaper 3 slightly downwards acts at the position 3P that the roll paper 3strikes the first guide surface 30. This force acts as resistanceagainst the guide surface 30 guiding the roll paper 3 diagonallyupwards, so that the position 3P that strikes the first guide surface 30becomes hard to slide upwards, which means that the state of theperiphery of the striking position 3P is stabilized and the curl can bestably removed.

However, depending on the paper quality and/or condition of the rollpaper 3, the position 3P that the roll paper 3 strikes the first guidesurface 30 may move upwards along the first guide surface 30. In such acase, at the periphery of the position 3P, the angle between the guidesurface 30 and the direction of the roll paper 3 striking the guidesurface 30, which is the effective angle E, is reduced, so that itbecomes uneasy to remove the curling tendency. In the printer 1, the tippart 21 a of the plate part 21 in the line thermal head 15 thatfunctions as the second paper guide extends to the close to the guidesurface 30, so that the position 3P that the roll paper 3 is striking isstable and dose not move away upwards. Accordingly, the roll paper 3 ismade resistant to folding and the paper feeding force is transmitted tothe position 3P, so that the curling can be efficiently removedcontinuously. The distance L between the output tip or output end 21 aof the second paper guide and the first guide surface 30 shouldpreferably be set at 5 mm or below.

By making the corner 24 of the tip part 21 a a right angle or an acuteangle, the position 3P where the roll paper 3 strikes the guide surface30 becomes more difficult to move upwards. This also maintains thedirection of the roll paper 3 striking the first guide surface 30 at thefirst direction φ1 and the angle θ with the slant S of the guide surface30. Also, the roll paper 3 tilts downwards somewhat at the position 3Pdue to the curl, so that the angle at which the roll paper 3 strikes theguide surface 30 is always larger than the angle θ between the guidesurface 30 and the paper feeding direction φ1. Accordingly, themechanism of this invention uses the curl itself conversely for easilyremoving the curling tendency of the roll paper 3.

From the view point of the platen roller 16, the paper feeding directionφ1 is decided as a direction of a tangent at the point where the thermalhead 15 contacts the platen roller 16. However, by the angle of the tippart 21 a of the plate part 21 that functions as the second paper guide,the angle of striking the paper to the guide surface 30 can becontrolled and more preferable conditions for removing the curl can beproduced or controlled. In the same way, by changing the slant of thefirst guide surface 30, the conditions for removing the curl can bechanged.

In order to make rigid the roll paper 3 against the folding over, thedistance R between the platen roller (feed roller) 16 and the firstguide surface 30 and/or the distance L between the tip part 21 a and thefirst guide surface 30 should preferably be made short. In order toefficiently remove the curl, the slant S of the first guide surface 30with respect to the first direction φ1 and/or the angle θ shouldpreferably be made large. However, if the roll paper 3 is pushed withtoo much pressure against the first guide surface 30 and/or if the angleof the roll paper 3 striking the first guide surface 30 (this anglebeing determined by the relative angle between the first guide surface30 and the line thermal head 15 that forms the second surface) becomestoo large, there is the possibility of a fall in the quality of theprint outs due to the roll paper 3 being overly deformed, curling theopposite way and/or creases being produced in the roll paper 3, etc.

In the printer 1 of the present embodiment, a shaft 31 that extendsparallel in the axial direction of the platen roller 16 is provided forthe first paper guide 25, with the first paper guide 25 being able torotate about this shaft 31. Using this shaft, the first output guide 25can also slide in the forward and backward. Therefore, by moving thefirst paper guide 25 itself and/or operating the shaft 31 from theoutside, the slant S of the first guide surface 30 and the distance Lbetween the first guide surface 30 and the tip part 21 a can beadjusted. When the strength of the curling tendency of the roll paper 3changes due to the roll paper 3 being consumed and the diameterchanging, or the paper quality of the roll paper 3 has been changed, thepaper guide 25 can be set in a suitable state for removing the curl. Inplace of the first paper guide 25, the angle or position of the tip part21 a of the line thermal head 15 may be controlled.

In the printer 1 that includes the paper feeding apparatus 40, the curlcan be removed by striking the roll paper 3 to the first guide surface30 on the exit side of the platen roller 16. Accordingly, there is noneed for the roll paper to be squeezed by a roller or spring to removethe curl and the resistance for feeding the roll paper is decreased. Theload applied to the motor is reduced, and a motor 18 with a small outputcan be used, so that it is possible to make the housing 2 of the printer1 compact. In addition, the power consumption of the motor 18 isreduced, so that it is possible to extend battery life.

When the curl was removed by squeezing with rollers or a spring, etc.,it is necessary to pull the roll paper through such a mechanism, so thatit has been necessary to locate the apparatus for de-curl between theroll of paper and the platen roller. With the method of the presentembodiment, the curl is removed by striking the roll paper 3 to thefirst guide surface 30, so that the de-curling mechanism can beinstalled at the exit side of the platen roller, near the exit opening4. Accordingly, it is easy to add a de-curl mechanism as an option andto add a de-curl mechanism to a conventional printer. In the printer 1,a mechanism for de-curling is realized by arranging according to thepresent invention, the output paper guide 25, the platen roller 16, andthe line thermal head 15, those are the members that compose theperiphery of the exit opening 4 of the thermal printer 1. This meansthat very few parts or members and very little space need to be added,so that the curl of roll paper can be removed in an extremely compactmanner and at low cost.

For stretching out of the curl, it is thought that removing the tendencyby extending the inner side of the curled part is important. In methodswhere the curl is removed while pulling the roll paper, since forces areapplied to both the inner side and the outer side of the curled part, itis difficult to efficiently make the difference between these forceslarge. In the printer 1, the curl is removed while pushing the rollpaper 3. Accordingly, it is possible to extend only the inner surfacewithout applying an extending force to the outer surface of the curledpart. In addition, using the folding resistivity of the paper, acompressing force that acts in a contracting direction can be generatedin the outer surface of the curled part. Accordingly, this aspect of thepaper feeding apparatus 40 and/or printing mechanism 10 of the printer 1of the present embodiment is extremely efficient at removing the curl.

In addition, in the printer 1, the curl is removed on the output sidenear the platen roller 16 while the paper is being pushed and paperfeeding is reliably performed in this area, so that there is also themerit that it is difficult for paper jams to occur. If the paper jamoccurs, the paper jam is located near the exit opening 4, so it is easyto remove the jam.

So long as the platen roller 16 is not driven and paper is not fed, noforce is applied to the part 3P of the paper that strikes the firstguide surface 30. Accordingly, when printing by the printer 1 isinterrupted and the platen roller 16 is not rotating, even if the rollpaper strikes the guide surface 30 and bends in the opposite direction,very little force acts on that part 3P, so that no tendency to curl inthe opposite direction is imparted. Accordingly, it is not necessary toperform special control, such as control to rotate the platen roller 16in reverse for preventing the counter curl.

The paper feeding apparatus 40 according to the present invention and aprinter that uses such paper feeding apparatus 40 are not limited tothose described above. The printer may have a paper pass where the rollpaper is not reversed at the platen roller. The discharge direction forthe paper is not limited to the upper surface of the housing. The sidesurface or bottom surface may be freely selected and the first guidesurface of the present invention can be arranged in any arrangement.

The printer 1 a shown in FIG. 3 is a different example of the presentinvention. In this printer 1 a, the printing mechanism 10 and a paperfeeding apparatus 40 a have been separated. In this printer la, the rollpaper unit (roll) 3 r is set at the back B of the housing 2 and the rollpaper 3 is fed towards the front F by a printing mechanism 10 includingthe line thermal head 15 and the platen roller 16, then the curl isremoved by a paper feeding apparatus 40 a that discharges the paper. Thepaper feeding apparatus 40 a includes a discharge roller 41, asub-roller 42, an outlet guide 25 that guides the roll paper 3 to theexit opening 4, and a paper guide 45 that leads roll paper 3 from thedischarge roller 41 to the close of the outlet guide 25. The dischargeroller 41 corresponds to a feed roller, the sub roller 42 corresponds toa paper holding member, and the output or outlet guide 25 corresponds toa first paper guide that includes a first guide surface 30. The paperguide 45 corresponds to a second paper guide that has the second guidesurface 19.

In the paper feeding apparatus 40 a, the outlet guide 25 is rotatedand/or slid with the shaft 31, and the second paper guide 45 is alsoslid in the forwards-backwards direction and rotated with the shaft 46.Accordingly, the direction in which the roll paper 3 strikes the firstguide surface 30 can be adjusted more freely, so that it is possible toappropriately correct curling tendencies of different conditions.

FIG. 4 shows yet another example. A printer 1 b of this example includesa paper feeding apparatus 40 b. The paper feeding apparatus 40 bincludes a fourth paper guide 58 that has guide surfaces 56 a and 57 athat face one another in order to lead the roll paper 3 from the outputside of the platen roller 16 to the first guide surface 30.Additionally, out of two members 56 and 57 disposed up and down of thefourth paper guide 58, a part 59 on the output side of the upper member56 is disposed at a closer position to the first guide surface 30 so asto be the second guide surface 19.

In the paper feeding apparatus 40 b, the roll paper 3 that has beenoutputted from the platen roller 16 is linearly guided to the firstguide surface 30 inside a tiny space between the guide surfaces 56 a and57 a. Accordingly, even if the distance between the platen roller 16 andthe first guide surface 30 is increased, the roll paper 3 can beprevented from folding without sagging. Accordingly, the force that hasfed the paper push the roll paper 3 against the first guide surface 30,so that the same situation is made as above, the curl is stably removedfrom the roll paper 3. This construction is suited to adding a functionof the present invention for removing the curl to an existing printer orto a printer in which the first guide surface 30 cannot be disposed nearthe platen roller 16. As one example, it is possible to lead the rollpaper 3 to an existing housing wall or to the outside by the two members56 and 57 and arrange the first guide surface 30 for de-curling.

In the paper feeding apparatus 40 b, the first paper guide 25 and thebottom member 57 of the fourth paper guide 58 may be integrated. Withthe shaft 46, the upper member 56 of the fourth paper guide 58 isrotated and/or slid for controlling the angle and position of the part59 of the exit side that functions as the second paper.

FIG. 5 shows yet another printer 1 c according to the present invention.This printer 1 c has a paper feeding apparatus 40 c of the presentinvention installed upstream of the printing mechanism 10. In thisprinter 1 c, the roll paper 3 is led to a flat platen 36 by the paperfeeding apparatus 40 c and a print head, such as an ink jet head 35,that is opposite the flat platen 36 and moves in the scanning directionprints on the roll paper 3. Alternatively, the head 35 may be a wire-dottype. Also, in place of a serial printer in that printer head moves inthe scanning direction, the printer may be a line printer that printsentire line at ones or a page printer such as a laser printer. Theprinted roll paper 3 is guided to the exit opening 4 by dischargerollers 51 and 52.

The paper feeding apparatus 40 c of the present example includes a feedroller 43, a paper guide 44 that is the paper holding member and alsothe third paper guide, and a flat platen 36. The flat platen 36corresponds to the first paper guide. A part on the output side 45 ofthe paper guide 44 corresponds to the second paper guide that includesthe second guide surface 19. The curl of the roll paper 3 fed by thefeed roller 43 and the plate 44 is removed on the flat panel 36, so thatprinting can be performed on flat paper using an ink jet method or thelike. Accordingly, high-quality printing can be performed even on rollpaper. When an ink jet method is used, it is hard to hold and feed thepaper in a state where the ink has not dried after printing for de-curl,though there are no such worries with the arrangement in the presentexample. In addition, the print quality can be raised. Since the paperfeeding apparatus 40 c is constructed on only the paper feeding side Bof the ink jet head 35, problems such as deterioration in print qualitydue to the paper feeding apparatus 40 c dirtying the surface of rollpaper 3 that has been printed upon do not occur.

In the paper feeding apparatus 40 c of the present embodiment, the plate44 is slid in a diagonal direction, so that the distance between theplate 44 and the flat platen 36 can be controlled. By rotating the plate44, the angle at which the roll paper 3 is bent at a surface (the firstguide surface) 30 of the flat platen 36 can be adjusted.

FIG. 6 shows yet another printer 1 d according to the present invention.This printer 1 d is equipped with a paper feeding apparatus 40 d whichremoves the curl in the same way as in the printer 1 shown in FIG. 1,and in which the thermal head 15 is used as a paper holding member andthe platen roller 16 is used as a feed roller. The roll 3 r or paper,the platen roller 16, and the thermal head 15 are aligned in that order,the thermal head 15 is disposed so as to be approximately vertical, sothat the platen roller 16 can be moved upwards and removable, and whenthe platen roller 16 has been removed, the entire paper route appears,so that it is easy to set the roll paper and to remove paper jams,thereby making the printer easy to handle.

However, in the printer 1 d, the roll paper 3 is discharged on theopposite side to the supply direction with the printed surface 3 b onthe reverse or facing downwards. It is undesirable that the printedsurface is not visible. Also, in view of when the printer is installedwith a mobile terminal 7 such as that shown in FIG. 7, it is notpreferable for the paper 3 that has been discharged to cover and hide aliquid crystal panel 7 a and a keyboard. When the printer is installedin or with the mobile terminal 7, as shown in FIG. 7, it is preferablefor the print surface 3 a to be visible and for the liquid crystal 7 ato not be hidden by the print outs.

The higher the angle θ of the first guide surface 30 with respect to thedirection φ1 in which paper is fed by the platen roller 16, the greaterthe curl-removing performance. In particular, when a diameter of rollpaper 3 is so small such as 10 mm or below, the roll paper 3 has strongcurl, so that the angle θ should preferably be large, and maintain anangle of 45 degrees or above. Considering an arrangement in which suchangle θ is maintained, the print surface is made visible, and thedischarge direction is on the roll paper side, the arrangement shown inFIG. 1 is unavoidable where the thermal head 15 is arranged horizontallyabove the platen roller 16. However, this arrangement is not so goodconsidering how to remove the platen roller 16. Therefore, an automaticpaper feeding mechanism to the platen roller or an opening or openingsfor removing paper jams may be required. While this may be acceptablefor a slightly large printer, such as a desktop printer, for anextremely compact printer that can be installed with a mobile phone, theother solution is required for easily handle.

In FIG. 8, a cross-sectional view shows the overall construction of yetanother printer 1 e according to the present invention. The printer 1 eis shown with a similar size to the examples described above, however isan extremely small printer that uses a paper roll 3 r with a diameter of10 mm or below and outputs flat print outs with the curl removed. Insidethe housing 2, the paper roll 3 r, the platen roller 16, the thermalhead 15, and the motor 18 that drives the platen roller 16 are arrangedin an approximately straight line or are aligned almost horizontally. Apaper guide 17 with a U-shaped guide surface 17 a is disposed below theplaten roller 16, and a paper pass 50 is constructed. In the paper pass50, paper 3 pulled from the paper roll 3 r leads around the outercircumference of the platen roller 16 and the reverse side of the paper3 is outputted so that an inner surface 3 a of the roll paper 3 facesthe printing surface 15 a of the thermal head 15. The thermal head 15 isdisposed so that the printing surface 15 a is approximately vertical,and the printed roll paper 3 is fed by the thermal head 15 and theplaten roller 16 in an approximately vertical direction and is outputtedto the outside from the exit opening 4 provided in the upper part of thehousing 2.

A discharge paper guide (the second paper guide) 21 that includes aguide surface (the second guide surface) 19 for guiding the roll paper 3from the platen roller 16 in the vertical direction, a cutter 60 thatincludes a movable blade 61 and a fixed blade 62, and an outlet guide(first paper guide) 25 that includes a guide surface (first guidesurface) 30, which is tilted so as to guide the inner surface 3 a of theroll paper 3 and bend the discharge direction towards the outer surface3 b of the roll paper, are disposed between the platen roller 16 and thedischarge opening 4 in that order from below. The outlet guide 25 isdisposed so as to appear on the surface 2 a of the housing 2 and coverthe discharge opening 4. In the printer 1 e, the paper feeding apparatus40 e comprises the line thermal head 15, the platen roller 16, the firstpaper guide 25, and the second paper guide 21, so that the curlingtendency (curl) of the roll paper 3 is removed by the roll paper 3 beingpushed against the guide surface 30 located at the discharge opening 4and the paper is discharged to the surface 2 a of the housing 2.

The movable blade 61 and the fixed blade 62 of the cutter 60 aredisposed in parallel along the surface of the housing 2 just below theoutput guide 25. The movable blade 61 of the cutter 60 is positionedabove the platen roller 16, so that the movable blade becomes the upperblade with respect to the fixed blade 62 that is positioned on theopposite side above the line thermal head 15, and moves perpendicular tothe roll paper 3 in the horizontal direction. Accordingly, thedischarged roll paper 3 is cut directly below the outlet guide 25, andprint outs are discharged in the form of flat sheets where the curl hasbeen straightened out.

The discharge paper guide 21 is positioned above the platen roller 16,and functions as the second paper guide of the paper feeding apparatusdescribed above by contacting the outer surface 3 b of the roll paper 3and guiding the roll paper 3 in an approximately straight line to thevicinity of the movable blade 61 from the platen roller 16 withoutfolding the roll paper 3.

In addition, the printer 1 e includes a means 70 that operates inaccordance with the diameter of the paper roll 3 r and indicates aposition of the outlet guide 25. The indicator 70 includes two arms 71and 72 that rotate around a shaft 16 a of the platen roller 16, with thearm 71 contacting the outer circumference of the roll paper unit 3 r anddetecting the diameter of the roll 3 r. A front end 73 of the other arm72 appears at the surface 2 a of the housing 2 and rotates incoordination with the arm 71 so that a value corresponding to thediameter of the roll 3 r is indicated by the front end 73 of the arm 72.Accordingly, the extent of the curl that changes according to thediameter of the roll 3 r can be easily understood at the surface of thehousing 2, so that the user can adjust the position of the outlet guide25 to a position that is suited to removing the curl.

FIG. 9 shows how the paper roll paper 3 r is set. In the printer 1 e,the platen roller 16 and the thermal head 15 are disposed in thehorizontal direction (the first direction) from the side of the roll 3r. The printing surface 15 a of the line thermal head 15 is arranged soas to extend upwards (vertically, or in a second direction that isperpendicular to the first direction) at approximately a right angle tothe horizontal direction, and so does not interfere with the platenroller 16 when the platen roller 16 is moved away upwards. The platenroller 16 can be removed or moved away towards a side above the printermain body 28 without obstruction of the line thermal head 15.

The platen roller 16, the discharge guide 21, the movable blade 61, andthe outlet guide 25 are attached to the roll paper cover 27appropriately. When the roll paper cover 27 is rotated in order to setthe roll 3 r, the platen roller 16, the discharge guide 21, the movableblade 61, and the outlet guide 25 move together with the roll papercover 27 so that the paper storage unit 11 and the paper pass 50 appear.Accordingly, as shown in FIG. 9, the roll 3 r is inserted in the paperstorage unit 11 and by pulling out the end part 3 c from the upper partof the roll 3 r with the inner surface 3 a facing the direction of thepaper pass 50 below, the roll paper 3 can be set in the printer 1 eextremely easily.

That is, after the roll 3 r has been inserted into the storage unit 11and the paper cover 27 has been closed, as shown in FIG. 10 the platenroller 16 returns to the position above the feed guide 17, the outersurface 3 b of the roll paper 3 is pressed by the platen roller 16 andthe roll paper 3 is nipped between the feed guide 17 and the platenroller 16. By doing so, the roll paper 3 is set in the U-shaped paperroute 50 along the guide surface 17 a of the feed guide 17. The reverseside of roll paper 3 is led by the paper route 50 and the inner surface3 a is guided towards the printing surface 15 a of the thermal head 15,so that printing is performed on the inner surface 3 a of the roll paper3.

Once the roll paper 3 that has been pulled from the roll 3 r has beenset, the end part 3 c of the roll paper 3 that is pulled passes abovethe fixed blade 62 and extends in the opposite direction to a normaldischarge direction, the normal discharge direction is the direction tothe roll 3 r. After the roll paper cover 27 has been closed, the cutter60 is operated, and the movable blade 61 moves and the end part 3 c iscut off. Accordingly, in the printer 1 e, by simply opening the rollpaper cover 27, inserting the roll paper unit 3 r, pulling out the endpart 3 c of the roll paper 3 so as to extend beyond the paper route 50,closing the roll paper cover 27, and by having the cutter 60 move once,the roll paper 3 is set in a state where printing is possible.Accordingly, the task of replacing the roll paper and putting theprinter 1 e into the standby mode is extremely easy.

After the roll paper 3 has been set, the roll paper 3 is inside theU-shaped paper pass 50 and the end of the roll paper 3 is positionedupstream of the cutter 60, and is in approximately straight. The end ofthe roll paper 3 is not pushed onto the outlet guide 25, so that the endof the roll paper is not significantly curved or folded and no tendencyto bend in the opposite direction to the curl is imparted, so that thereis no deterioration in the quality of the paper.

FIG. 11 shows how to print the roll paper 3. When print data is suppliedto the line thermal head 15 and the platen roller 16 is moved by themotor 18 via a suitable driving mechanism such as a gear train or thelike. The roll paper 3 is held between the line thermal head 15 and theplaten roller 16 and fed upwards while printing is performed on theinner surface 3 a. The printed roll paper 3 is led to the guide surface30 of the output guide 25 through the cutter 60 with the outer surface 3b being guided in an approximately straight manner by the guide surface19 of the discharge guide 21. The inner surface 3 a of the roll paper 3strikes the guide surface 30, and the roll paper 3 is bent by the angleof the guide surface 30 by the guide surface 30 in the direction to theouter surface 3 b of the roll paper 3, that is, the opposite directionto the curling tendency or curl, and is discharged from the dischargeopening 4 in the direction of the roll paper cover 27.

In the paper pass 50, the roll paper 3 is bent so that the outer surface3 b is placed on the inside, the platen roller 16 presses the outersurface 3 b and the roll paper 3 is guided in an approximately U-shape.That is, the roll paper 3 is also bent in the opposite direction to thecurl inside the paper route 50. Accordingly, so long as the curlingtendency of the roll paper is not strong, the curl becomes somewhat weakby the paper pass 50. When the diameter of the platen roller 16 issmall, the ability to weaken the curling tendency may be increased byreduced radius of curvature of the paper pass 50. However, with thisU-shaped paper route 50 alone, there is not such a pronounced weakeningeffect for the curl. In the small printer 1 e, the diameter of the rollpaper 3 set in the printer is also small, so that the curl is sostronger. Accordingly, just after the paper has been fed from the platenroller 16, the curl is little weakened, so that the roll paper 3 at thatpoint will be curled with the outer surface 3 b in a convex state.

In the printer 1 e, the roll paper is guided from the paper route 50 tothe outlet guide 25 without folding and with the paper being pushed soas to bend in the opposite direction to the curl, so that print outsthat are approximately straight are obtained from the outlet guide 25.The discharge guide 21 is disposed at the exit of the platen roller 16,and between the platen roller 16 and the cutter 60, the outer surface 3b of the roll paper 3 is guided in an approximately straight manner bythe guide surface 19 of the discharge guide 21. Accordingly, the rollpaper 3 is prevented from becoming convex on the outer surface 3 b side.Also, the end of the roll paper 3 catches on the fixed blade 62 aftercutting by the cutter 60 and this acts as a guide so as to prevent theroll paper 3 from becoming curve to the inner surface 3 a side.Accordingly, the roll paper 3 that is outputted from the platen roller16 is guided in an approximately straight manner to the guide surface 30of the outlet guide 25 that is disposed directly above the cutter 60.This means that in the same way as in the various examples describedabove, the curling tendency of the roll paper 3 is successivelycorrected by the guide surface 30, and paper in the form of flat sheetsthat are not curled is discharged from the discharge opening 4. At thispoint, the printed roll paper 3 exits in the direction of the outersurface 3 b by the outlet guide 25, so that the roll paper 3 isdischarged with the printed inner surface 3 a oriented as the surface,so that the user can see the printed surface 3 a.

The diameter of the roll paper to be set in the small printer 1 e willbe around 10 mm, the angle θ between the direction the roll paper 3striking the guide surface 30 and the direction of the guide surface 30shall be 60 degrees or above, with an angle of 70 to 80 degrees, forexample, being even more preferable. When the diameter of the roll paper3 is 10 mm or below, it is preferable for the angle θ to be as close aspossible to 90 degrees or above. In addition, when the distance L cannotbe made especially small, it is necessary to increase the angle θ. Byincreasing the angle at which the roll paper is bent towards the outsideto around 110 degrees, it is possible to obtain a sufficient de-curleffect even if the distance L is not especially reduced.

In the printer 1 e, the inner surface 3 a of the roll paper 3 isprinted, so that it is possible for the angle θ by which the roll paperbends to the outside to be set at 90 degrees or above. The angle θ canbe increased within the tilting of the printing surface 15 a of thethermal head 15 faces upward, and the platen roller 16 can be disposedabove the printing surface 15 a. By this kind of arrangement, the platenroller 16 can be removed upward without interfering with the thermalhead 15, so that the roll paper or roll itself 3 r can be set extremelyeasily. In such arrangement, since the roll paper 3 becomes slanted withrespect to the direction in which the movable blade 61 moves, cuttingability is slight reduced. The movable blade 61 can be disposed so as tobe perpendicular to the roll paper 3 but would end up being disposed atan angle to the surface of the housing 2 or the cover 27, which canreduce the space efficiency. In the printer 1 e shown in FIG. 8, theroll itself 3 r, the platen roller 16, and the head 15 are aligned in anapproximately straight line in the horizontal direction, and theprinting surface 15 a of the head 15 rises almost vertically so as to beperpendicular to this arrangement, so that the movable blade 61 isarranged along the cover 27 and can move in a direction that isperpendicular to the feeding direction of the roll paper 3, with spacebeing used extremely efficiently in this arrangement.

The angle θ and the distance L should preferably be adjusted inaccordance with the strength of the curling tendency of the roll paper3, but it may not be necessary to adjust according to the condition ofthe curl particularly so often. However, for a compact printer 1 e, theroll paper unit 3 r has a small diameter, and the amount of paper on theroll is small, so that paper is wounded to the minimum diameter as faras possible. Accordingly, there is an extremely large difference in theusable diameter of the roll 3 r at the start and at the end of use.

For the above reason, in the printer 1 e, as shown in FIG. 12, theoutlet guide 25 is attached to the housing 2 so as to slide in thefront-back direction (the directions F and B in the drawing). Therefore,the position of the tilted guide surface 30 is changeable so that thedistance L between the guide surface 30 and the end part 21 a of thedischarge guide can be adjusted. In addition, the indicator 70 thatmoves in the direction of the arrow in accordance with the diameter ofthe roll paper unit 3 r is provided. Accordingly, the user can slide theoutlet guide 25 in the front direction F or the back direction B basedon the indication by the end 73 of the arm 72 of the indicator 70, andcan thereby adjust the gap L to a suitable distance for removing thecurling tendency.

The printer 1 is easy to maintain when a printer jam has occurred. Thatis, in the cutter 60, the movable blade 61 is disposed above the platen16 and is also on the outlet guide 25 side of the fixed blade 62 so asto become the upper blade with respect to the fixed blade 62 that isdisposed above the line thermal head 15. Accordingly, if a paper jamoccurs when the movable blade 61 moves and the movable blade 61 and thefixed blade 62 are positioned above one another, the movable blade 61can be released upwards without interfering with the fixed blade 62, asshown in FIG. 9, so that the paper jam can be removed. Furthermore, themovable blade 61 is arranged on the platen roller 16 side, and thedischarge guide 21 and the output guide 25 are arranged so as to movetogether with the platen roller 16, so that when there is a paper jam,regardless of the state of the movable blade 61, the movable blade 61can be moved without interfering with the other members and without themovable blade 61 and the platen roller 16 interfering with one another.Accordingly, in the printer 1 e, even when a paper jam has occurred, theroll paper cover 27 can definitely be opened, so that the entire paperroute 50 appears and paper jams can be easily removed.

After cutting, the end of the roll paper 3 is supported by the fixedblade 62 that is disposed above the line thermal head 15. Accordingly,as described above, the end of the roll paper 3 is guided approximatelyvertically and made to strike the guide surface 30 of the outlet guide25 more precisely. By cutting the roll paper 3 upstream from the outletguide 25, the amount of paper that needs to be fed in order to cut theroll paper 3 can be reduced, which can stop the roll paper from beingwasted and can prevent the print region from being limited. In addition,by cutting the roll paper 3 with the cutter 60 that is disposed in frontof (upstream from) the outlet guide 25, there is an additional merit inthat the roll paper 3 is not pressed against the guide surface 30 untilpaper feeding is performed and a curling tendency in the oppositedirection is not imparted into the roll paper 3.

The printer 1 e is a roll paper printer, and when it is attached to amobile terminal such as the mobile phone 7 and used, print outputs thatdo not curl can be outputted with the upward printed surface and withoutthe display 7 a or the keyboard of the mobile terminal being hidden.Additionally, the electric parts such as the line thermal head 15 andthe motor 18 can be disposed on the side connected to the mobileterminal and the roll paper can be disposed on the side away from themobile terminal so that the paper roll itself 3 r is easy to replace andit is easier to provide a large space for storage. Accordingly, it ispossible to provide a compact printer that is suited to being carriedtogether with a mobile terminal, such as a mobile phone or a PDA, and tobeing used while the user is out of office.

In a case where the discharge guide 21 is omitted from the printer 1 e,it is necessary to dispose the guide surface 30 of the output guide 25in the vicinity of the platen roller 16, and in view of interferencewith the platen roller 16, the range of angle θ of the bending at theguide surface 30 becomes limited. Accordingly, it is preferable toprovide the discharge guide 21 and to provide a suitable space betweenthe platen roller 16 and the outlet guide 25, so that it possible tosecure the angle θ for the guide surface 30. Also, the roll paper isguided in a straight line by the discharge guide 21, so that even if areasonably large gap is provided for disposing the cutter 60, the rollpaper 3 can be kept in a state where is difficult for the roll paper 3to become folded over. The cutter 60 may be omitted, and the outletguide 25 may be provided with a manual cutter function.

Also, in place of the indicator 70, it is possible to provide a linkmechanism that can adjust the position of the outlet guide 25 incoordination with the diameter (remaining diameter) of the paper roll 3r, with it also being possible for the gap L to be adjustedautomatically according to the diameter of the paper roll unit 3 r.Furthermore, it is also possible to control the rate of removal of thecurling tendency of the roll paper by changing the angle θ of the guidesurface 30 in place of, or together with, control over the gap L asdescribed above.

In addition, it is possible to print on the inner surface 3 a of theroll paper 3 using a different method such as by an ink jet head. Whileexamples of where the paper feeding apparatus of the present inventionis installed in a thermal printer or an ink jet printer have beendescribed above, so long as roll paper is used, the present invention isnot limited to various printers and can be applied to other printingapparatuses, such as facsimiles and plotters.

INDUSTRIAL APPLICABILITY

As described above, the present invention provides a paper feedingapparatus and a printing apparatus that are extremely compact and canremove the curling tendency of roll paper. In this invention, by usingroll paper, it is possible to realize a compact, handy-type printingapparatus that can be easily carried together with a mobile terminalsuch as a mobile phone, and can be used anywhere, with it also beingpossible to obtain print outs in the form of sheets. Accordingly, it ispossible to provide, in addition to a desktop roll paper printer,facsimile machine, plotter, or copier, a printer that is suited to beinginstalled in a mobile appliance, such as a mobile phone or PDA, and aprinter that is also suited to being carried together with such a mobileappliance.

1. A paper feeding apparatus, comprising: a feed roller and a paperholding member for nipping and feeding roll paper; a first paper guidethat has a first guide surface against which an inner surface of theroll paper outputted from the feed roller is pushed, the first guidesurface being tilted so as to guide the roll paper in a directionopposite to a curving direction of the roll paper; and a second paperguide that has a second guide surface which leads the roll paper to thefirst guide surface with guiding an outer surface of the roll paper, anoutput end of the second guide surface being located in the vicinity ofthe first guide surface, wherein a part of the roll paper that strikesor contacts the first guide surface is bent sharply with an angle of atleast 45 degrees in compressing condition for removing a curl of theroll paper.
 2. A paper feeding apparatus according to claim 1, whereinthe first guide surface is tilted by around 45 degrees or above withrespect to a direction in which the roll paper strikes the first guidesurface.
 3. A paper feeding apparatus according to claim 1, furthercomprising a third paper guide in which the paper holding member and thesecond paper guide are integrated.
 4. A paper feeding apparatusaccording to claim 1, further comprising a fourth paper guide that hasguide surfaces which face one another so as to lead the roll paper froman output side of the feed roller to the first guide surface, wherein anoutput side of the fourth paper guide is the second paper guide.
 5. Apaper feeding apparatus according to claim 1, wherein a distance betweenthe first guide surface and the output end of the second guide surfaceis 5 mm or shorter.
 6. A paper feeding apparatus according to claim 1,further comprising means for adjusting an angle between the first guidesurface and the second guide surface and/or a distance between the firstguide surface and the output end of the second guide surface.
 7. A paperfeeding apparatus according to claim 6, further comprising means forindicating an adjustment amount for the means for adjusting in relationto a remaining diameter of the roll paper.
 8. A paper feeding apparatusaccording to claim 6, wherein the means for adjusting adjusts incoordination with a remaining diameter of the roll paper.
 9. A paperfeeding apparatus according to claim 1, wherein a corner of a tip of thesecond paper guide is a right angle or an acute angle.
 10. A printingapparatus including the paper feeding apparatus according to claim 1 anda print head for printing on the roll paper.
 11. A printing apparatusaccording to claim 10, wherein the print head is a thermal head doublesas a paper feeding member, and the feed roller is a platen roller thattogether with the thermal head nips and feeds the roll paper.
 12. Aprinting apparatus according to claim 10, wherein the first paper guideis a flat platen and the print head prints onto the roll paper that issupported by the first guide surface.
 13. A printing apparatus accordingto claim 12, wherein the print head moves along the first guide surface.14. A printing apparatus according to claim 10, further comprising apaper path that leads the inner surface of the roll paper to the printhead, wherein the feed roller contacts the outer surface of the rollpaper and feeds the roll paper towards the first guide surface.
 15. Aprinting apparatus according to claim 14, wherein the first paper guidedischarges the roll paper along a surface of a main body of the printingapparatus in a direction in which the roll paper is supplied.
 16. Aprinting apparatus according to claim 14, further comprising, betweenthe first paper guide and the feed roller, a cutter that has a movableblade that moves in a direction for cutting the roll paper.
 17. Aprinting apparatus according to claim 16, wherein the movable blade isdisposed between the first paper guide and the second paper guide.
 18. Aprinting apparatus according to claim 16, wherein the movable blade isdisposed on the feed roller side, and further comprising a fixed bladethat is fixed on the print head side and is provided on an opposite sideof the first paper guide to the movable blade.
 19. A printing apparatusaccording to claim 18, wherein the first paper guide, the movable blade,and the feed roller are detachable from a main body of the printingapparatus.
 20. A printing apparatus according to claim 18, furthercomprising a roll paper cover that opens and closes with respect to amain body of the printing apparatus when the roll paper is attached,wherein the first paper guide, the movable blade, and the feed rollermove together with the roll paper cover with respect to the main body ofthe printing apparatus.
 21. A printing apparatus according to claim 20,wherein the first paper guide discharges the roll paper in a directionof the roll paper cover.
 22. A paper feeding apparatus according toclaim 1, wherein the roll paper output from the feed roller isdischarged with striking the first guide surface after the roll papercontacts with the output end of the second guide surface.
 23. A paperfeeding apparatus according to claim 1, wherein the first paper guide isa flat platen.